1. Field of the Invention
The invention relates to a plate-cylinder bearing arrangement for a printing press wherein at least one plate cylinder is displaceable with its shaft, and a side-register adjusting device serves for position correction.
In rotary printing presses for multi-color printing, the problem arises that the registers of the different colors must be in agreement with one another. For this purpose, the plate cylinders are aligned precisely with respect to one another, all of the plate cylinders being are adjusted to the axial position and the circumferential position of one of the plate cylinders. The invention relates to a plate-cylinder bearing arrangement by means of which the side register is adjustable or correctable.
Heretofore known from the published German Patent Document DE-OS 27 20 313 is a plate-cylinder bearing arrangement wherein the plate cylinder with its shaft is displaceably supported in a bushing. The side register correction or adjustment is effected by providing a sliding bushing permanently disposed on the plate-cylinder shaft, the sliding bushing being engaged by a swivel lever which is adjustable through the intermediary of a worm-gear drive.
In order to determine the register error or deviation, a specimen print is made initially at the start of a new printing job. The side and circumferential registers are then corrected. Because of the specimen print, however, the printing press is in the "impression on" position. In this position, Schmitz rings or cylinder bearers, which are disposed at the ends of the cylinders, are pressed onto each other with high forces. Correspondingly high forces act upon the shafts of the plate cylinders, and a displacement in the axial direction requires that very high frictional forces in the respective bearings be overcome. This calls for a high expenditure of force for adjustment, as well as expensive and elaborate bearings. Alternatively, it is necessary to move to the "impression off" position in order to adjust or correct the side register. The latter solution, however, results in the loss of valuable time.